A badly injured whale which became trapped in a sea loch off Lewis has died, rescuers have confirmed.
It had been hoped the whale would find its way back to sea
The northern bottle-nosed whale became beached in Loch Roag, on the west of the Hebridean island, on Monday morning before managing to free itself.
It later vanished and experts hoped it had managed to find its way back to the open ocean.
But the whale, which was severely underweight, was found dead at about 1030 BST on Tuesday at Garynahine.
Volunteers from British Divers Marine Life Rescue (BDMLR), which specialises in rescuing stranded whales and dolphins, said the creature, which is not thought to have been particularly old, appeared to have died of natural causes.
Scientists from the Scottish Agricultural College will carry out a post-mortem examination on the carcass, which is to be removed by the local authority.
Tony Woodley of BDMLR said rescuers had feared the worst when they noticed how thin the 20ft long adult was.
He added: "We didn't manage to get a good look at the whale while it was swimming in the loch but it did appear to be very thin and in quite poor condition.
"It clearly had something wrong with it and it is a deep sea creature that shouldn't be in shallow waters, so when you add all that up its death was not really unexpected, unfortunately.
"Our guys got there as quickly as they could when we learned the whale had re-stranded at Garynahine but by then there was really nothing they could do and it was just a case of letting nature take its course."
The search for the whale had been called off due to bad light at about 2130 BST on Monday, but was resumed on Tuesday morning.
It had first been spotted in the loch at about 0900 BST on Monday. The regular bursts from its blow hole were used to mark its course around the loch.
Blood was seen around its dorsal fin and in the shallow water where it was swimming.
Local fishing and fish farm boats kept clear while the whale was swimming around the loch and Northern Constabulary asked the public to stay away from the area until further notice because of the risk of contamination from the whale's wounds.
Northern bottle-nosed dolphins are only found in the north Atlantic, where they prefer water deeper than 1,000m and normally travel in groups of up to 10.
Small numbers live around the Northern and Western Isles of Scotland and the west of Ireland, but they are most commonly found off Norway and the Barents Sea.
Last year, a female bottle-nosed whale died after becoming stranded in the River Thames.